1. Technical Field
The present invention relates to a projector.
2. Related Art
FIGS. 12A to 12C are diagrams for explaining a related projector 900A. FIG. 12A is a diagram showing an optical system of the related projector 900A, and FIGS. 12B and 12C are diagrams for explaining problems in such the related projector 900A.
This projector 900A is a hold-type display apparatus, in which liquid crystal devices 400R, 400G and 400B used as an electro-optical modulators have luminance characteristics as shown in FIG. 12B. Therefore, the projector 900A has a problem that smooth dynamic picture display cannot be obtained because of a so-called persistence of vision, which is different from the case of a CRT which is an impulse-type display device having luminance characteristics as shown in FIG. 12C (regarding this persistence of vision, refer to, for example, “Image Quality of Dynamic Picture Display in Hold-type Display” (Technical Report by The Institute of Electronics, Information and Communication Engineers, EID 99-10, Page 55 to 60 (1999-06)).
FIGS. 13A to 13C are diagrams for explaining another related projector 900B. FIG. 13A is a diagram showing an optical system of another related projector 900B, and FIGS. 13B and 13C are diagrams showing an optical shutter used in the projector 900B.
In this projector 900B, as shown in FIG. 13A, on the light incident sides of liquid crystal devices 400R, 400G and 400B, optical shutters 420R, 420G and 420B are arranged thereby to cut off light intermittently, so that the above problem is solved. Namely, persistence of vision is softened, and the smooth dynamic picture display of good quality can be obtained (refer to, for example, JP-A-2002-148712 (FIGS. 1 to 7)).
However, in such the related projector, there is a problem in which since the light is intermittently cut off by the optical shutter, efficiency of light utilization lowers greatly.